Management of the runoff from contributing impervious area (CIA) surfaces must be provided in the project design. For ODOT, the CIA consists of all impervious surfaces within the strict project limits, plus impervious surface owned or operated by ODOT outside the project limits that drain to the project via direct flow or discrete conveyance.

Management and treatment of stormwater entering ODOT right-of-way is the responsibility of the adjacent property owner.